Inertia compensating device for printing press with reciprocating type bed



Aug. 12, 1958 A. BUTTNER 2,347,208

INERTIA COMPENSATING DEVICE FOR PRINTING PRESS WITH RECIPROCATING TYPEBED 2 Sheets-Sheet 1 Filed NOV. 21. 1955 Z @7 [Li 2/ 6 2,847,208PRINTING PRESS E BED 1958 A. BUTTNER INERTIA CQMPENSATING DEVICE FORWITH RECIPROCATING TYP Filed Nov. 2-1, 1955 2 Sheets-Sheet 2 FIG. 6.

United States Patent INERTIA "COWENSATING DEVICE FOR PRINT- 'ING PRESSWITH RECIPR-O'CATING BED.

Artur Biittner, Heidelberg, Germany, assignor to SchnellpressenfahrikAktiengesellschaft. Heidelberg, Heidelberg, Germany, a corporation ofGermany Application November 21, 1955, Serial. No. 548,208,

Claims priority, application Germany-December 4, 1-954 5 Claims.(Cl..267-.,75)

This invention relates to apparatus for compensating the force ofinertia of the reciprocating: type bed of a cylinder press.

During the reciprocating movement of the type bed of a cylinder printingpress, there arise considerable forces of inertia which increase withincrease of the operating speed. In order to compensate these forces ofinertia, there have hitherto preferably been used air buffers by meansof which the forces generated by the movements ofthe type bed were.absorbed at the reversing points of the movement thereof, and theenergy thus stored used for assisting the reverse movement. In theseprior arrangements of such air buffers, the buffer pistons andconnectingrods-one of two at each end of the type bedare connecteddirectly or by means of'pedestal bearings with the type bed itself,while the buffer cylinders associated therewith are anchored firmly tothe machine frame. Thus the buffer pistons andconnecing rods participatein the type bed movement and hence increase the moving mass. Moreover,as the buffer pistons continuously. slide in and out of the cylinders,the flexible cup sleeves, which are used in most cases, are nottroublefree in operation without constant attention.

Due to these faults in air buffer arrangements, attempts have been madeto dimension the type bed gearings so that the forces of inertia may beabsorbed without the use of air buffers. Such steps, however, arecontrary to the aim of further increasing the output; of a cylinderpress.

The length of the buffer cylinders, incidentally, has allowed them to beused only with those types of mechanical press in which the type bed,after covering a certain distance at a uniform speed, is slowed down toa standstill and is subsequently accelerated again. Withnonuniform typebed movements, i. e. sinusoidal or approximately sinusoidal movements,for example in stop-cylinder presses, it was not possible to use airbuffers, although considerable forces of inertia arise with these kindsofmovements.

The compensation of energy previously proposed for stop-cylinder pressesby means of a tension spring, allows only an insufficientcompensationofthe force of inertia owing to the impossibility ofdimensioning the springs.

to do the job adequately.

In order to rem-ovethese disadvantages in compensating the forces ofinertia of the reciprocatedtype bedbymeans of air compression, it isproposed in the presentinvention, to couple an air cushion herein termedan, air compressor,

preferably a rotary compressor, with the drive of the type bed, wherebythe oscillating piston or vane: of, the compressor is driven by a shaftrotating, in, alternate directions.

The oscillating piston or vane of the compressor; .01

2,847,268 Patented Aug. 12, 1958 sections wherein no compression takesplace. The oscillating vane may for this purpose, swing in aclosedhousing, in which there, is disposed an intermediate distance piece orcross piece comprising a partition wall, so that theoscillating vane mayswingto and fro from one side of the partition wall to the other,whereby the air enclosed between the vane and the partition wall isalternately compressed and expanded. Thus there results a simple anduninterrupted compensation of the inertia forces .occurring during theslowing down and acceleration of the type bed. The type bed is free ofadditional weight, by which there is attained a reduction of the forcesof inertia to be compensated. Depending upon the position of the slotsfor the air intake into the housing,

. it is possible to select the compression pressures to conformapproximately to the force curves of the type bed movement.

The apparatus proposed by the invention is suitable for stop andswinging cylinder machines, and also for single and two revolutionmachines. By suitably arranging the ports inthe casing of the enclosedcompressor, it is possible to adapt the compression curve to allthetypes of movements which are employed. The compensation of theinertiaforces not only causes a reduction of wear of the drivingmembers, but it is also possible consequently to attain increasedprinting outputs with machines of given dimensions.

Ayfurther advantage over the know buffer arrangements consists in thattheback pressure occurring during the compression strokes is transmittedto'the machine frame in :an opposite direction to the force of inertiaof the type bed. The stability of the machine is thusconsiderablyimproved without fastening it to the floor.-

The invention will be described'further, by way of example, withreference .to the accompanying drawings, in which:

Fig. l isa sectional side elevation of a part of mechanical press havingan inertia compensating apparatus constructed in accordance with theinvention,

Fig. 2 is a cross-section of the press taken on the line Fig. 1,

Fig. 3 is a section taken on the line BB of Fig. 2, for a cylinderpress-having a uniformly moved type bed andashort reversing movement, i.e. for single and two revolution machines,

Fig. 4 is an operating diagram showing the variations of the force ofinertia occurring during one cycle of 360 and the compression curve withthe, cylinder housing constructed according to Fig. 3,

Fig. 5 is a view similar to that of Fig. 3, but for a cylinder presshaving a non-uniform, i. e. sinusoidal or approximately sinusoidicallymoved type bed motion, as with stop and swinging cylinder mechanicalpresses.

Fig. 6 is an operating diagram for a stop or swinging cylindermechanical press with the cylinder housing constructedaccording to Fig.5.

Referring first-1y to Fig. l and 2', on the underside of a type bed 1,which carries a form 2, there-is fixed a rack bar 3 which engages with agear wheel 4. During alternating rotation of the gear wheel4, forexample, through angular displacement X, the type bed 1 is reciprocatedin known manner alonga straight line, running on several rollers 6 whichare guided in corresponding tracks of the machine frame 5. The flat form2 moves underneath inking rollers '7 of the inking mechanism, wherebythe fiat form 2 is inked, and subsequently the printing of the sheet'bymeans of the printing cylinder 3 is effected when the type bed passesunderneath it. The known arrangements of mechanical presses such as thetype bed drive, printing cylinder, inking mechanism and so forth are notparticularly illustrated in the drawings, since they are .well known anddo not form a part of the invention. The gear wheel 4, which effects thereciprocation of the type bed, is mounted on a shaft 9 which in turn isrotatably supported in known manner in the frame 5. The gearing for thealternating rotation of the shaft 9 is not shown and may likewise be ofknown construction.

For purposes of the present invention, the end of the shaft 9 supports avane 11 which is additionally supported by a ring 10, the latter alsobeing rigidly connected with the shaft 9. The van 11 thus also rotatesthrough the angle X in a cylindrical housing or casing 12 which isscrewed to the machine frame 5. Screwed firmly in the housing 12 thereis a distance piece 13, which may also be termed a cross piece. The ring10, on rotation of the shaft 9, rotates in a curved recess of thedistance piece 13. Mounted on the housing 12 are poppet valves 14, whichare guided in an insertable bearing member 15 anchored to the housing.Counteracting the weight of the poppet valve 14 is a compression spring16, which is supported against an abutment 17 fixed on the bearingmember 15. An adjustable compression spring 16 tends to maintain thevalve plate in an upward position until an adjustable stop ring 18 bearson the abutment 17. Fig. 1 shows the left-hand valve in section, whilethe right-hand valve is shown in elevation.

Depending on the kind of movement, which the type bed undergoes, thereare provided in the housing 12, ports 19 and 20 (Fig. 3) or 21 (Fig. Thehousing 12 is closed by means of an end cover 22 (Fig. 2).

The method of operation of the apparatus for compensating the force ofinertia is as follows:

On alternating rotation of the shaft 9 for producing the reciprocatingmovement of the type bed, the vane 11, which is connected with the shaft9, is moved in the housing 12 in a circular path. Thus, each time thevane passes the air slots 19, 20 (Fig. 3) or 21 (Fig. 5), the enclosedair is compressed to several atmospheres. Due to this compression of theenclosed air, the type bed movement is additionally delayed, while afterpassing the dead center position, the air expanding again with therotary movement in the opposite direction, assists the acceleration ofthe type bed by means of the release of the stored energy during theexpansion stroke.

The compensation of the force of inertia is effected,

depending upon the kind of type bed movement in such a manner thataccording to Figs. 4 and 6 the acceleration and delaying pressures whicharise are completely or approximately balanced by the compressionpressure.

When the cylinder housing is constructed according to Fig. 3 with ports19 and 21), there are created three chambers in the casing, namely aneutral chamber a, and two compression chambers b and c.

With the construction according to Fig. 5 having only port 21 in thehousing 12, the neutral chamber is omitted and there are only the twocompression chambers e and 7.

Depending on the construction of the housing 12, as shown by theoperating diagrams according to Figs. 4 and 6, it is possible tocompensate extensively the force of inertia of any kind of type bedmovement.

In the operating diagrams of Figs. 4 and 6, the forces of inertiaoccurring in one cycle, through 360, are denoted by P and P, While thearea of the diagram bounded by the compression curve is shaded anddenoted by J.

The force generated by the pressure rise while compressing the enclosedair are transmitted by the distance piece or cross piece 13 to thehousing and thus on on to the machine frame. This back pressure actingon the vane 11 acts in an opposite direction to the movement of the typebed, which considerably improves the stability of the machine on thefloor, and renders unnecessary floor fastenings otherwise required withhigh operational speeds.

With drives in which the shaft for transmitting the reciprocating typebed movement executes nearly a complete revolution or more, a reductiongear is incorporated,

so that the rotary piston or vane executes no more that about threequarters of a revolution.

In order to adapt the compression pressures to thz various operationalspeeds or the resultant forces of inertia respectively, knownarrangements may be used tc cause a variation of the compression chamberor of the air supply to be compressed.

Adjusting the compression pressures to the diversifiec operating speedsand the corresponding forces of inertia is also possible by the diskvalves 14-, the function 01 which can be affected by their constructionand adjustment: The compression spring 16 is constructed in such a waythat its spring tension is somewhat greater than the weight of the diskvalve 14 so that the latter is lifted in the state of rest up to thestop 17. When the rotary piston 11 is moved, the air can enter withoutdifficulty on the suction side through the lifted valve into the suctionchamber of the pump. On the compression side of the piston, i. e. in thecompression chamber of the pump, the increasing air pressure effects theclosing of the other valve 14 to be found on this side, providing thepiston speed and with that, the surge of air pressure is sufiicientlystrong enough. The closing of this valve depends upon several factors,namely upon the dimension of the valve disk, the height of the valveupstroke and includes the cross section of passage, which can beregulated by means of the adjustable stop ring 18, and also depends uponthe pressure spring 16 which can also be adjusted. The interaction ofthese three factors result that the closing of the valve duringcompression stroke is only effected as of a corresponding printingspeed. As a rule, the valves are constructed and adjusted in such a waythat the compression effect and with that the compensation of theinertia forces of the type bed of cylinder machines having approximately5000 I. P. H. (impressions per hour) performance arises only at animpressional speed of approximately 2500 I. P. H. The valves 14 remainopen at speeds lower than approximately 2500 I. P. H. so that there isno compression effect. The forces of inertia which change according tothe square of speed are relatively weak in small-sized cylinder machinesat speeds lower than 2500 I. P. H. so that within this lower range ofspeed the compensation of inertia forces by the nearly unchangingcompression forces would not provide any advantage.

What I claim and desire to secure by Letters Patent is:

1. In a printing press having a frame of the reciprocating type bed, arotary air cushion for compensating the forces of inertia of said typebed during its reciprocation comprising a cylindrical casing anchored onsaid frame, a vane coupled with said type bed and movable arcuately insaid casing throughout the movement of said type bed, and a radial vanefixed in said casing, cooperating with said movable vane, said casingbeing provided with at least one port opening to the atmosphere andspaced circumferentially from said fixed vane to locate said selectedportions of said casing, each portion alternately comprising compressionand expansion portions in said casing.

2. Compensating device according to claim 1, in which there are at leasttwo such ports spaced circumferentially from one another.

3. Compensating device according to claim 1, in which valves adjacentsaid fixed vane connect the interior of said casing with the atmosphere,said valves being biased to close when a predetermined pressure isattained in said casing, and means normally biasing said valves in openposition.

4. In a printing press having a frame and a reciprocating type bed,drive means including a rotary shaft for reciprocating said bed and adevice for compensating the forces of inertia of said type bed duringits reciprocation comprising an enclosed rotary air cushion, said aircushion comprising a casing mounted on said frame with said shaftextending axially into said casing, a vane fixed on said shaft andmovable arcuately in said casing and a radial vane fixed in said casingand cooperating with said movable vane to alternately define compressionand expansion portions in said casing, the angular position of saidmovable vane on said shaft being such that said movable vane approachessaid fixed vane as said bed approaches the ends of its stroke, theforces arising from the compression of air between said fixed andmovable vanes being transmitted through said drive means to the bed tocounteract the inertia of said bed.

5. In a printing press having a frame and a reciprocating type bed, adevice for compensating the forces of inertia of said type bed duringits reciprocation, comprising an air cushion mounted on said frame andhaving a relatively oscillatable casing and vane, said casing having aradial partition anchored to said casing, said casing being providedwith ports radially disposed, said ports communicating with theatmosphere, said vane cooperat- References Cited in the file of thispatent UNITED STATES PATENTS 404,394 Feister June 4, 1889 420,012 HuberIan. 21, 1890 2,621,036 Rother Dec. 9, 1952

